This invention relates to methods and apparatus for determining traffic information in a communications network e.g. to facilitate route planning and resource allocation.
Communications packet networks are currently being developed for the transport of multimedia services including voice and data traffic. The services carried by such networks vary considerably in their transport requirements. For example, best effort data services can tolerate delay or loss of packets, whereas voice services require guaranteed quality real time virtual conventions.
These differing traffic requirements can pose significant problems for a network management system which is used to control resource allocation and to determine routing so as to guarantee service to high Q0S traffic that is admitted to the network. This is a particular problem in a MPLS network.
A further problem has become apparent with the introduction of packet networks having an optical core. Within the core of such a network, buffering or queuing of packets arriving at a router poses a severe problem. There is thus an increasing need to control packet flow at the network edge to ensure that, before packets are launched into the network core, sufficient resources are available to process these packets so as to avoid the need for buffering. This in turn requires a means of measuring bandwidth occupancy in the various parts of the network so that resources can be allocated appropriately.
Currently, a simple network management protocol (SNMP) is employed to provide measurements of link occupancy within the network. However, this protocol provides no information as to the quality of service level of the traffic, and further generates a large volume of signalling traffic. This signalling traffic is of course non-revenue earning and thus reduces the potential revenue return to the network operator.
An object of the invention is to minimise or to overcome the above disadvantages.
A further object of the invention is to provide an improved arrangement and method for link occupancy measurement within a network.
Another object of the invention is to provide and improved arrangement and method for resource allocation within a network.
According to the invention there is provided a method of determining traffic information in a communications packet network comprising a plurality of regions, the method comprising, within each network region, maintaining a database of traffic information for that region, and polling the databases of selected other regions to which packets are to be routed so as to determine resource availability for those packets.
According to another aspect of the invention there is provided a method of controlling packet flow and allocating resources in a communications packet connection network partitioned into a plurality of regions and carrying a core network and a plurality of edge routers providing access to the core network, the method comprising; within each region, maintaining a database of traffic information from that region, and, at each edge router, determining from traffic information stored in the database of the region containing the edge router and from databases of other regions to which packets are to be routed, a measure or resource availability for a packet to be routed in order to allocate resources to route said packet.
According to a further aspect of the invention there is provided a method of scheduling despatch of information packets at an edge router in a communications packet network in a network comprising an optical core network of core routers interconnected by links and a plurality of edge routers providing access to the core network, said network being partitioned into a plurality of regions, each said region being provided with a respective network information database, the method comprising; determining within each region link occupancy data and storing that data in the respective network information database, and, at an edge router, acquiring said link occupancy data from the network information databases in those network regions through which packets are to be routed so as to schedule the despatch of that packet into the core network so as to schedule despatch of those packets at a rate commensurate with resource availability within the core network.
According to another aspect of the invention there is provided software stored on a storage medium in machine readable form for scheduling despatch of information packets at an edge router in a communications packet network in a network comprising an optical core network of core routers interconnected by links and a plurality of edge routers providing access to the core network, said network being partitioned into a plurality of regions, each said region being provided with a respective network information database, wherein the software is arranged to perform the method steps of; determining within each region link occupancy data and storing that data in the respective network information database, and, at an edge router, acquiring said link occupancy data from the network information databases in those network regions through which packets are to be routed so as to schedule the despatch of that packet into the core network so as to schedule despatch of those packets at a rate commensurate with resource availability within the core network
According to another aspect of the invention there is provided a communications packet network comprising an optical core network of core routers interconnected by links and a plurality of edge routers providing access to the core network, said network being partitioned into a plurality of regions, each said region being provided with a respective network information database, wherein the network incorporates means for determining, within each region, link occupancy data and for storing that data in the respective network information database, and wherein each said edge router has means for acquiring said link occupancy data from the network information databases in those network regions through which packets are to be routed so as to schedule despatch of those packets into the core network at a rate commensurate with resource availability within the core network.
According to a further aspect of the invention, there is provided an edge router for providing access to a communications packet network comprising an optical core network of core routers interconnected by links, said network being partitioned into a plurality of regions, each said region being provided with a respective network information database containing link occupancy data, and wherein each said edge router has means for acquiring said link occupancy data from the network information databases in those network regions through which packets are to be routed so as to schedule despatch of those packets into the core network at a rate commensurate with resource availability within the core network
In a preferred embodiment, the traffic information comprises link occupancy measurements on a per-traffic or quality of service class basis.
Advantageously, the system incorporates distributed software objects running on core router that log the traffic data and respond to request when polled from edge routers.
Depending on local network occupancy levels, the acquired data may be xe2x80x98pulledxe2x80x99 from selected network database on an as-needed basis, or particular databases may xe2x80x98pushxe2x80x99 or broadcast their information into the network.
The Information retrieved by the edge router may advantageously be used to control routing and transport of traffic across the network traffic by a way a dynamic pricing arrangement. The data or link occupancy information that is gathered can be employed to calculate notional resource price or so-called n-price for network bandwidth based on the current occupancy of a preferred route is described in U.S. Pat. No. 6,671,285 (Kirby et. al.) issued Dec. 30, 2003, the contents of which are incorporated herein by reference. The rate at which packets are scheduled for despatch by a router is a function of the current value of the n-price.
The traffic flow is a function of a number of parameters, the dominant factors being provisioning potential and resource admittance/availability.
In a further embodiment, an edge router may reduce the need for signalling traffic by the use of prediction techniques to determine estimated data values.
An edge router may determine a lifetime for its stored link occupancy data, and acquire new data only at the expiry of that lifetime
Advantageously, communication between the databases and the core and edge routers is effected via a common software bus.